This algorithm solves the game by assigning the unsolved cell with one of the possible values available in a Trail and Error method, starting from the least possible value. If the value entered is already present in the related blocks of the cell, then it becomes invalid and hence, that value can't be assigned for that cell.Therefore the process repeats with the other possibilities in the cell unless the cell becomes solved. This algorithm can be applied only if the cell has the possible values less than or equal to 3. It is used when the cell remains unsolved and there is no chance for the other algorithms to be appiled to solve that particular cell.
Here, we consider an example of solving a cell.To solve the cell,the least possible value of the cell 3 is chosen and is examined with the values of the cells in the related blocks.
Since, the value 3 is not already assigned to any other cell.The cell taken to solve is set with 3 and therefore this value 3 is removed from the set of possibilities of other cells in the related blocks.Likewise,cells can be solved by assigning the possible values available in a trail and error method.